KMT-2021-BLG-1077L: The fifth confirmed multiplanetary system detected by microlensing

Abstract

The high-magnification microlensing event KMT-2021-BLG-1077 exhibits a subtle and complex anomaly pattern in the region around the peak. We analyze the lensing light curve of the event with the aim of revealing the nature of the anomaly. We test various models in combination with several interpretations. We find that the anomaly cannot be explained by the usual three-body (2L1S and 1L2S) models. The 2L2S model improves the fit compared to the three-body models, but it still leaves noticeable residuals. On the other hand, the 3L1S interpretation yields a model explaining all the major anomalous features in the lensing light curve. According to the 3L1S interpretation, the estimated mass ratios of the lens companions to the primary are $\sim 1.56\times 10^{-3}$ and $\sim 1.75\times 10^{-3}$, which correspond to $\sim 1.6$ and $\sim 1.8$ times the Jupiter/Sun mass ratio, respectively, and therefore the lens is a multiplanetary system containing two giant planets. With the constraints of the event time-scale and angular Einstein radius, it is found that the host of the lens system is a low-mass star of mid-to-late M spectral type with a mass of $M_{\mathrm{h}}=0.14_{-0.07}^{+0.19}{M}_{\odot }$, and it hosts two gas giant planets with masses of $M_{{\mathrm{p}}_1}=0.22_{-0.12}^{+0.31}{M}_{\mathrm{J}}$ and $M_{{\mathrm{p}}_2}=0.25_{-0.13}^{+0.35}{M}_{\mathrm{J}}$. The planets lie beyond the snow line of the host with projected separations of $a_{\perp ,{\mathrm{p}}_1}=1.26_{-1.08}^{+1.41}\mathrm{AU}$ and $a_{\perp ,{\mathrm{p}}_2}=0.93_{-0.80}^{+1.05}\mathrm{AU}$. The planetary system resides in the Galactic bulge at a distance of $D_{\mathrm{L}}=8.24_{-1.16}^{+1.02}\mathrm{kpc}$. The lens of the event is the fifth confirmed multiplanetary system detected by microlensing following OGLE-2006-BLG-109L, OGLE-2012-BLG-0026L, OGLE-2018-BLG-1011L, and OGLE-2019-BLG-0468L.

arXiv comment9 pages, 8 figures

References in corpus (40)

• Galactic Stellar and Substellar Initial Mass Function
• A method for optimal image subtraction
• Discovery of a Cool Planet of 5.5 Earth Masses Through Gravitational Microlensing
• Reddening and Extinction Toward the Galactic Bulge from OGLE-III: The Inner Milky Way's Rv ~ 2.5 Extinction Curve
• Real-Time Difference Imaging Analysis of MOA Galactic Bulge Observations During 2000
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF
• The angular size of dwarf stars and subgiants - Surface brightness relations calibrated by interferometry
• OGLE-2003-BLG-262: Finite-Source Effects from a Point-Mass Lens
• The Use of High Magnification Microlensing Events in Discovering Extra-solar Planets
• Discovery of a Jupiter/Saturn Analog with Gravitational Microlensing
• Microlens OGLE-2005-BLG-169 Implies Cool Neptune-Like Planets are Common
• Expanding the Realm of Microlensing Surveys with Difference Image Photometry
• A Natural Formalism for Microlensing
• Difference imaging photometry of blended gravitational microlensing events with a numerical kernel
• MOA-2011-BLG-293Lb: A test of pure survey microlensing planet detections
• Toward a Deterministic Model of Planetary Formation VI: Dynamical Interaction and Coagulation of Multiple Rocky Embryos and Super-Earth Systems around Solar Type Stars
• Stellar Contribution to the Galactic Bulge Microlensing Optical Depth
• The Mass Spectrum Of Machos From Parallax Measurements
• Masses and Orbital Constraints for the OGLE-2006-BLG-109Lb,c Jupiter/Saturn Analog Planetary System
• Microlensing by Multiple Planets in High Magnification Events
• Gravitational lens under perturbations: Symmetry of perturbing potentials with invariant caustics
• An Earth-mass Planet in a 1-AU Orbit around an Ultracool Dwarf
• A Neptune-mass Free-floating Planet Candidate Discovered by Microlensing Surveys
• The second multiple-planet system discovered by microlensing: OGLE-2012-BLG-0026Lb, c, a pair of jovian planets beyond the snow line
• A Jovian analogue orbiting a white dwarf star
• Predictions for Microlensing Planetary Events from Core Accretion Theory
• Revisiting the microlensing event OGLE 2012-BLG-0026: A solar mass star with two cold giant planets
• Properties of Microlensing Light Curve Anomalies Induced by Multiple Planets
• OGLE-2017-BLG-1522: A giant planet around a brown dwarf located in the Galactic bulge
• OGLE-2018-BLG-0567Lb and OGLE-2018-BLG-0962Lb: Two Microlensing Planets through Planetary-Caustic Channel
• KMT-2017-BLG-2820 and the Nature of the Free-Floating Planet Population
• Analysis of Microlensing Light Curves Induced by Multiple-Planet Systems
• OGLE-2018-BLG-1011L\lowercase{b,c}: Microlensing Planetary System with Two Giant Planets Orbiting a Low-mass Star
• Where Are the Binary Source Gravitational Microlensing Events? II
• A Likely Detection of a Two-Planet System in a Low Magnification Microlensing Event
• KMT-2021-BLG-1077L: The fifth confirmed multiplanetary system detected by microlensing
• One Planet or Two Planets? The Ultra-sensitive Extreme-magnification Microlensing Event KMT-2019-BLG-1953
• KMT-2021-BLG-0240: Microlensing event with a deformed planetary signal
• The Korea Microlensing Telescope Network (KMTNet) Alert Algorithm and Alert System
• A Pair of Planets Likely in Mean-motion Resonance From Gravitational Microlensing

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• VBMicroLensing: three algorithms for multiple lensing with contour integration
• OGLE-2018-BLG-0584 and KMT-2018-BLG-2119: two microlensing events with two lens masses and two source stars
• KMT-2021-BLG-0240: Microlensing event with a deformed planetary signal
• KMT-2022-BLG-0440Lb: A New $q<10^{-4}$ Microlensing Planet with the Central-Resonant Caustic Degeneracy Broken
• Brown-dwarf companions in microlensing binaries detected during the 2016--2018 seasons
• Mass Production of 2021 KMTNet Microlensing Planets III: Analysis of Three Giant Planets
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• Mass Production of 2021 KMTNet Microlensing Planets II
• Simulations of Triple Microlensing Events I: Detectability of a scaled Sun-Jupiter-Saturn System